Energy, Mass, Waves, and Particles

Hi, Energy has mass, then does it mean waves also have mass as energy if they have short enough wavelengths? Why electrons behave like waves but when we carefully observe them, they behave like particles? Oh, sorry for a little bit random but why we can't harvest energy from nuclear fusion yet? Thank you.
- Duy (age 16)
Arizona

Inertial energy and mass are the same thing, measured in units that different by a factor of c². So yes, waves have mass. In fact, all known objects consist of quantum waves, so waves had better have mass..

Electrons behave like waves in many ways. They show diffraction patterns and other interference effects. We can measure these things, so it's not right to say they quit behaving like waves when we measure them. It depends on what we measure. They do show particle-like behavior in one important way. If we measure how much electronic charge arrives somehere, we get numbers like 0, -1e, -2e, .... rather than just a continuous range of possibilities. That's different from the classical waves we usually think about. It's just like counting particles. I wish I could explain why quantum objects (electrons, protons, photons,...), all the ingredients of the world, act this way, but I just can't think of a simple way to describe it.

On the side question, it's very hard to get nuclei to fuse. They have to ram into each other at very high energy. One way to do that is to make a hot dense plasma of them, but it's extremely hard to keep it from leaking away. Another way is to compress little pellets by hitting them with very powerful light beams from all directions at once. Then the explosive energy has to be caught, and the process starts over. It's not as easy as it sounds.

Mike W.

(published on 12/29/2013)